Earth SC-202 Physical Geology

Instructor

• • • • • • Prof. Steven Dutch Office: LS 402 Phone: 465-2246 Email: [email protected]

Home Page: www.uwgb.edu/dutchs Office Hours MWF 10:30-11:30, TR 9:30-10:50

Soils What is Physical Geology?

Erosion Wind Weathering

Water

Oceans Underground Surface Sedimentary Glaciers Fossils Earth History

Rocks

Volcanoes Metamorphic Earth’s Interior Igneous

Plate Tectonics

Earthquakes Mountains Mineral Resources Intrusions

Other Planets

Syllabus

• • • • • • • • • Introduction to the course Minerals Igneous Rocks and Volcanoes Weathering and Erosion Evolution of Landscapes Sedimentary Rocks Evolution, Fossils, Geologic Time Glaciers Wind and Wave Erosion • • • • • Metamorphism and Deformation Earthquakes and Earth's Interior Continental Drift and Plate Tectonics Resources from the Earth Geology of other Worlds

Exams and Grading Midterm I 50 points Midterm II 50 points Lab 100 points Final Field Trip 80 points 20 points Attendance 10 points

A AB B BC C CD D

270+ 255-269 240-254 225-239 210-224 205-210 200-204

Total 300 points

Field Trip • • • • • • • Dates Mandatory – Absence Excuse Required 8:00 LS Parking Lot, Return 4:15 Casual Clothing – No strenuous hiking Bring a lunch and fluids Rest stops provided Put on your calendar! No excuses!

Lab

• • • Instructor: Jennifer Wessel Enroll in one section 100 points total

Expectations

• • • • Commitment – Focus in class Professional Conduct – No talking, texting – Stay whole period – Stay vertical and awake Use Syllabus Know your ID number or bring ID to exams

Sample exam question

• Which is the most desirable property in a gemstone?

a. High hardness b. Low hardness c. Excellent cleavage d. Density

Signs of Trouble

• • • • Not making connections – Lecture, lab, text, on-line, exams Not knowing your grade Not knowing what to study for Not knowing what’s on syllabus

Physics

Geology and Other Sciences

Chemistry Biology

•Geophysics •Seismology •Mineralogy •Petrology •Geochemistry •Paleontology •Paleo????ology

Astronomy

•Planetary Geology •Helioseismology

Geology

•Economic Geology •Hydrology •Engineering Geology •Historical Geology •Geomorphology •Oceanography •Structural Geology •Volcanology

Who Geoscientists Are:

• • • • About 30,000 in the U.S. Globally, in rich and poor countries, about one per $50 million GNP. Mostly male but changing rapidly (now about 25% female in U.S.) Still less than 10% minority in U.S. (moving up slowly)

Where Geologists Work

• • • 40 % Private Sector 30 % Academic 30 % Government

What Geologists Do:

• • • •

Locate Geologic Resources Geologic Hazard Mitigation

– Geological and Mining Engineering – Site Study – Land-Use Planning

Environmental Protection

– Environmental Impact – Ground Water and Waste Management

Basic Research (Furnishes fundamental knowledge for the applications)

Some Unique Aspects of Geology

• •

Importance of Relationships

Sequential Spatial

Importance of Time

• • • •

Distinctive Problems of Evidence

Slow Rates Rare Events Destruction of Evidence Inaccessibility

Some Geologic Rates • Cutting of Grand Canyon 2 km/3 m.y. = 1 cm/15 yr • Uplift of Alps 5 km/10 m.y. = 1 cm/20 yr.

• Opening of Atlantic 5000 km/180 m.y. = 2.8 cm/yr.

• Uplift of White Mtns. (N.H.) Granites 8 km/150 m.y. = 1 cm/190 yr.

Some Geologic Rates • Movement of San Andreas Fault 5 cm/yr = 7 m/140 yr.

• Growth of Mt. St. Helens 3 km/30,000 yr = 10 cm/yr.

• Deposition of Niagara Dolomite 100 m/ 1 m.y.? = 1 cm/100 yr.

1 Second = 1 Year • • • • • • • 35 minutes to birth of Christ 1 hour+ to pyramids 3 hours to retreat of glaciers from Wisconsin 12 days = 1 million years 2 years to extinction of dinosaurs 14 years to age of Niagara Escarpment 31 years = 1 billion years

Some Unique Aspects of Geology (Continued)

Reliance on Inference and Deduction • • • Intrinsically "Unsolvable" Problems Ancient Landscapes Mass Extinctions Ancient Ocean Basins

Scientific Principles in Geology

• • • Parsimony (K.I.S.S.) Superposition Uniformitarianism Using these, plus observation, we establish facts about Earth Processes

Parsimony

• • • The simplest explanation that fits all the data is preferred Doesn’t guarantee that things must be simple!

Theories with lots of ad hoc or unsupported ideas are probably wrong.

Parsimony: What is the best interpretation of this well data?

Parsimony • This?

• Or This?

Parsimony • • Rock layers throughout NE Wisconsin are nearly flat and little disturbed Glacial deposits are always on top of bedrock • Therefore this is the most likely interpretation

One Implication of Parsimony • •

How do we know the laws of nature are the same everywhere?

Out to the farthest stars, everything seems to obey the same laws of nature We find nothing in the rocks to suggest the laws of nature were different in the past • •

Either:

The laws of nature change but just happen to produce effects that look like the presently known laws of nature – or – The laws of nature really are the same everywhere

Another Implication of Parsimony • • We live in a universe of patterns If someone claims there is an exception to a known pattern, the simplest explanation is that he/she is wrong • Therefore the burden of proof in science is on the challenger

Superposition

• • • Whodunit?

Last night, one of Green Bay’s premier beer can collections was stolen The only clue is footprints in the snow The thief was the last person to leave the premises

The Suspects

• • • • • The Nephew The Maid The Cook The Handyman The Butler Has a seeing-eye dog Drives a car Rides a motorcycle Rides a bike Walks to work

• • • • • The Nephew has a seeing-eye dog The Maid Drives a car The Cook Rides a motorcycle The Handyman Rides a bike The Butler Walks to work The Crime Scene

Contacts

A Contact: Mindoro Cut, Wisconsin

Uniformitarianism

• • •

Continuity of Cause and Effect

Apply Cause and Effect to Future - Prediction Apply Cause and Effect to Present Technology Apply Cause and Effect to Past Uniformitarianism

Uniformitarianism does not mean:

• • • • • Catastrophes never occur Physical Conditions on Earth never Change Earth has always been the same Physical processes always occur at the same rate or intensity Laws of Physics have always been the same

Uniformitarianism does mean:

• • •

Using our knowledge of physical laws, we can test:

Whether catastrophes have occurred Whether physical conditions on earth have changed, and if so, how (ice ages, warm periods, high or low sea level, etc.) Whether physical laws themselves have changed in time, or elsewhere in the universe.